Date: Thu, 6 Jul 2000 15:51:34 -0400 (EDT) From: Zhihui Zhang <zzhang@cs.binghamton.edu> To: freebsd-hackers@freebsd.org Subject: Max DMA size Message-ID: <Pine.SOL.4.21.0007061545020.7314-100000@sol.cs.binghamton.edu>
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Can anyone tell me what factors determine the max DMA size (DMA counter on each controller or PCI bus related)? What is the typical max DMA size for a SCSI disk connected to a PCI bus? It seems to be much larger than MAXPHYS (128K). If so, does it mean we are not using full potential of DMA? So what's the problem if we enlarge MAXPHYS? Any help is appreciated. -Zhihui To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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